It is the knob and cable that sends heat to your legs when desired. It actuates a flap in the blower box that redirects air flow. The one that came with my Pushbutton car had a problem with the chrome peeling off the knob. I got a better one from Wilkinson that was used. It was his last one. I just now looked for my old one but it looks like I tossed it. Below is a photo of it installed and working correctly.
Do you have the knob and cable? Are you having trouble with your current parts?